is it enough, that the loading screen cames, if you choose a system?
start AM > press TAB key > General > Startup Mode : Show Display Menu > Exit AM
take a video file and rename it to your display-menu (for example : mame.mp4)
goto AM folder > menu-art > snap (depending to your display layout) > copy there your videofile
Next time you start AM, you see all your display. If you scroll to mame, you see your video loading
OR
instead menu-art folder :
take a video file and rename it to your display-menu (for example : mame.mp4)
goto AM folder > scraper/mame/flyer > copy there your video file